1. Field of the Invention
This invention relates, in general, to electromechanical apparatus and, more specifically, to generator end-winding support systems.
2. Description of the Prior Art
End-winding conductor supporting arrangements for turbine generators have conventionally used various forms of bracing rings and restraint assemblies or brackets which are generally attached to the end of the stator iron core assembly. Such arrangements have been satisfactory in many applications, but their use has certain inherent disadvantages when used in large turbine generators. The bracing rings and the winding conductors are secured to the brackets, usually by an arrangement of glass roping which extends around the conductors. When the temperature of the stator iron core increases, the thermal expansion pattern of the brackets tends to deflect the brackets outwardly away from the end-winding conductors. The resulting looseness between the brackets and the conductors, even when very minute, detrimentally affects the ability of the conductors to withstand the large forces encountered under overload current conditions and the constant forces encountered under normal current conditions without damage to the conductor.
The thermal expansion pattern of the conductors also causes the conductors to expand axially away from the stator iron core as the temperature increases. This movement also tends to increase the distance between the conductors and the brackets due to the conical configuration of the end winding conductors. Thus, the integrity of the bracing arrangement is degraded due to the movement of the conductors relative to the supporting brackets.
In addition to the above-mentioned temperature responsive movements, it has been found that it is difficult to maintain the dimensions of the end shield or support plate within the tolerances necessary to properly hold the brackets in the desired location. Also, the conventional end-winding conductor supporting arrangements have not provided sufficient flexibility to allow for tangential rotation of the end-winding assembly due to thermal changes. Therefore, it is desirable, and it is an object of this invention, to provide an end-winding conductor supporting arrangement which satisfactorily compensates for the axial and tangential movements of the winding assembly while still providing sufficient radial support therefor to withstand the radial forces encountered during normal and overload operating conditions.